Extensive observational evidence from core-collapse
supernovae such as SN 1987A indicates that some form of
large-scale hydrodynamic mixing process is required to
explain the resulting light curves, spectra, and velocity of
the heavier elements produced by explosive nucleosynthesis.
High-resolution 2D numerical simulations to date, however,
have been unable to reproduce these observations. An
experimental testbed has been designed to study in a
controlled laboratory setting some of the hydrodynamic
issues believed to be of importance in this problem. These
experiments are being conducted on the Omega Laser at the
Laboratory for Laser Energetics (LLE), University of
Rochester. To date, four separate aspects of the supernova
explosion problem have been studied. In all cases, radiation
from the Omega laser is used to drive a strong shock (M>>1)
into the target materials. In a first series of experiments,
a three-layer target with approximate density ratios of
10:1:0.1 was used to simulate the decreasing radial density
profile of a SN progenitor. This experiment addresses the
possible coupling, via propagation of a perturbed shock,
between instability growth and mixing at the simulated
(C+O)/He and He/H interfaces. A second series of experiments
focused on the effect of spherical divergence on the growth
of an initially imposed perturbation. Additional experiments
have been conducted to study the role of dimensionality (2D
vs. 3D initial perturbation) and modal content (single
wavelength vs. multi-mode perturbation) in the evolution of
a hydrodynamically unstable interface. In each case,
numerical simulations are found to provide reasonable
agreement with the experiments. Future work will aim to
combine the phenomena studied here in isolation, will move
toward more fully turbulent interface mixing, and will
explore possible non-symmetrical explosion scenarios.

Work performed for the US DOE by UC LLNL under contract
W-7405-Eng-48.